Internationally-minded American school districts/systems?

[Heliotrope]

If I were you (OP) I'd go with Thames Pirate's advice: focus on individual schools near college campuses in a liberal areas.
But I would just post on a forum/Reddit for domestic teachers, stating you're looking for schools that "really embrace internationalism, promote multilingualism and look to the future as core values of their daily operations". I'm sure you'll get lots of suggestions.

[PsyGuy]

I would concur with @Heliotrope, posting on a bigger message board such as Reddit or FB groups or the like with a bigger audience will garner you more responses. If you want another smallish board you may want to try the chat boards at Teachers.net
https://teachers.net/mentors/